Rust updates

[bearophile]

Marco Leise:

> Then again it also has 'begin' and 'end' instead of { and }. 
> Masochists...

Between APL/Ursala and Ada extremes there is a wide happy middle, 
D, Pascal and probably Rust too are all usable.

The 'begin' and 'end' of Pascal are not bad, they are short 
lowercase words written with common letters. I need to press 3 
not easy keys at the same time to print a single { in a text 
file. So probably writing "end" is about as fast or faster for me 
:-)

Bye,
bearophile